import java.io.File;
import java.util.Hashtable;
import java.util.Enumeration;
import javax.swing.*;
import javax.swing.filechooser.*;

public class EditorFileFilter extends FileFilter {

    private static String TYPE_UNKNOWN = "Type Unknown";
    private static String HIDDEN_FILE = "Hidden File";

    private Hashtable filters = null;
    private String description = null;
    private String fullDescription = null;
    private boolean useExtensionsInDescription = true;

    public EditorFileFilter() 
    {
	   this.filters = new Hashtable();
    }

    public EditorFileFilter(String extension) 
    {
  	   this(extension,null);
    }

    public EditorFileFilter(String extension, String description) 
    {
	   this();
       if(extension!=null) addExtension(extension);
       if(description!=null) setDescription(description);
    }

    public EditorFileFilter(String[] filters) 
    {
	   this(filters, null);
    }

    public EditorFileFilter(String[] filters, String description) 
    {
	   this();
       for (int i = 0; i < filters.length; i++) addExtension(filters[i]);
       if(description!=null) setDescription(description);
    }

    public boolean accept(File f) 
    {
	   if(f != null) 
	   {
	      if (f.isDirectory()) return true;
          String extension = getExtension(f);
	      if (extension != null && filters.get(getExtension(f)) != null) return true;
	   }
       return false;
    }

    public String getExtension(File f) 
    {
	   if(f != null) 
	   {
	      String filename = f.getName();
	      int i = filename.lastIndexOf('.');
	      if(i>0 && i<filename.length()-1) return filename.substring(i+1).toLowerCase();
	   }
       return null;
    }

    public void addExtension(String extension) 
    {
	   if(filters == null) filters = new Hashtable(5);
       filters.put(extension.toLowerCase(), this);
       fullDescription = null;
    }

    public String getDescription() 
    {
	   if(fullDescription == null) 
	   {
	      if(description == null || isExtensionListInDescription()) 
	      {
             fullDescription = description==null ? "(" : description + " (";
             Enumeration extensions = filters.keys();
             if(extensions != null) 
             {
		        fullDescription += "." + (String) extensions.nextElement();
                while (extensions.hasMoreElements()) 
                   fullDescription += ", ." + (String) extensions.nextElement();
		     }
		     fullDescription += ")";
	      } 
	      else fullDescription = description;
	   }
	   return fullDescription;
    }

    public void setDescription(String description) 
    {
	   this.description = description;
	   fullDescription = null;
    }

    public void setExtensionListInDescription(boolean b) 
    {
       useExtensionsInDescription = b;
	   fullDescription = null;
    }

    public boolean isExtensionListInDescription() 
    {
	   return useExtensionsInDescription;
    }
}
